A photo-thermo-refractive (PTR) glass based on SiO2-Al2O3-ZnO-Na2O (F, Br) glass system is prepared with a two-step melting process. The crystallization mechanism of PTR glass is studied by the transmittance spectrum, X-ray diffraction (XRD) and differential scanning calorimetry. It is demonstrated that the photosensitive spectrum of PTR glass is from 280 to 350 nm, the working spectrum is from 400 to 2700 nm, the optimum nucleation temperature is above 490 ℃, the crystallization temperature is near 595 ℃ and the crystalline phase is NaF. Volume Bragg grating (VBG) with the spatial frequency of 1000 mm-1 is recorded in PTR glass with direct laser interference patterning and “two-step” heat treatment process. The prepared VBG has a relative diffractive efficiency up to 91% and the angular filtering ability.